Biodiversity is the hotspot that includes various plants, animals, birds and microorganisms and the ecosystem they collectively form together. The tropical areas alone include about 50% of the world’s species. Many countries have varied rich biodiversity, including Bangladesh.

Bangladesh, situated at the Indo-Himalayan and Indo-Chinese sub-region intersection, is a hub of biodiversity. The fauna and flora are mainly present in the delta formed by Ganga and Brahmaputra in South Asia. This country consists of a wide diversity of natural ecosystems, including mammals, birds, reptiles, amphibians, and fishes. It is considered to be ecologically significant. Bangladesh signed a treaty to preserve the planet’s biological diversity in the year 1992 at the United Nations Conference on Environment and Development.

Bangladesh has a large and rich biodiversity. It is estimated that around 1952 species of invertebrates, 653 fish species, 49 amphibian species and approximately 137 reptile species exist in Bangladesh.

Moreover, Bangladesh is home to about 690 species of birds, including both local and migratory. Although most flora and fauna are identified, the primary data for some flora and fauna is still incomplete.

Flora

Bangladesh has a rich diversity of plants owing to its climate conditions and soil. Around 6000 plant species have been identified in Bangladesh, including more than 300 exotic species and 8 endemic species. Threatened species include about 95 vascular plants. Apart from various flowering plant species, Bangladesh has about 10,000 varieties of rice. Plant groups that are included in Bangladesh are as follows:

• Algae: There are sub-aerial, aquatic and terrestrial forms of algal species in Bangladesh. It includes the members of the family Chlorophyceae, Rhodophyceae, Xanthophyceae, etc. About 300 species of algae have been estimated from Bangladesh.
• Fungi: Fungi is limited in Bangladesh due to the unfavourable climate in Bangladesh. The fungi found here are the pathogens that infect various crops such as maize, rice, jute, sugarcane, potato, etc.
• Bryophytes: The smallest bryophyte, about  4mm, has been found in Bangladesh. Due to Bangladesh’s hot and humid climate, good growth of bryophytes such as Riccia, Marchantia etc., is observed.
• Pteridophytes: About 195 species of pteridophytes have been recorded in Bangladesh.
• Gymnosperms: It is estimated that about 7 naked seed plants of gymnosperms are found, including pine trees, Cycas and ornamental trees.
• Angiosperms: Bangladesh has about 3611 flowering plants that include both wild varieties and exotic species.

Fauna

A wide variety of vertebrates and invertebrates are found in Bangladesh, covering both terrestrial and aquatic habitats. The growth of insects is most favourable due to the warm and humid climate of the country. Due to the abundant Hilsa fish found here, it is considered the national dish of Bangladesh. It is home to a special kind of bird called the Robin. The largest living cat on the Earth, the Bengal Tiger, inhabits the mangrove forests of Sundarbans.

• Invertebrate fauna: This group is found in the majority, including mosquitoes, a variety of beetles, spiders, crustaceans, crabs and echinoderms such as starfish. Quite a few unique faunas which are not found anywhere exist in Bangladesh.
• Vertebrate fauna: It includes fishes, amphibians, reptiles, birds, and mammals. It is found that around 22,000 fish species, 5,000 amphibians, 7,400 reptiles, 9,000 birds and 4,500 mammals are present in Bangladesh.
• Fishes: Cyprinidae family forms the major fish species, including Carp and Barbs. A new species of eel, called Macrognathus aval, is now vulnerable. Hilsa fishery, the largest single-species fishery, contributes to major production from inland sources. The fish found in the swamp waters includes Anabas and climbing perch.
• Amphibians: Frogs and toads are the major animals in the class of amphibians. A variety of poisonous frogs with beautiful colour patterns are found, which can confuse nature enthusiasts. It also includes 8 threatened species. 
• Reptiles: Consist of turtles, tortoises, lizards, snakes, and crocodiles. The marsh crocodiles and Gharials are found in the swampy areas. The Sundarbans house the largest crocodile species called the “saltwater crocodile”.
• Birds: Sarus crane, which was abundant in Bangladesh before, has become rare. Few bird species, such as peafowl and pink-headed duck, have disappeared from Bangladesh.
• Mammals: It includes humans, tiny shrews, bats, and huge elephants.

Bangladesh is known for its forests all over the world. The trees are home to various types of birds. Mammals such as bats can be seen hanging on trees and looking for their prey at night. Bangladesh is famous for its swampy areas, and hence reptiles such as crocodiles and snakes can be seen all around, and one should be very careful.

Conclusion

Bangladesh harbours a diverse ecosystem that includes the world’s largest mangrove forest, Sundarbans. It is a natural habitat for various birds, animals and plants. This country also possesses varied faunal biodiversity. But many species are threatened due to the lifestyle of humans who cut trees for their own needs. Bangladesh, due to the high population density, unemployment, climate change, habitat loss, illegal actions in the forest, pollution, etc., is threatening its biodiversity. The government officials should take measures to cope with the current situation. They should spread awareness among the locals to preserve their natural resources. The current situation should be properly monitored, and the need for trained manpower should be met.